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Prolific integration of renewable energy sources (RESs) such as solar photovoltaic systems into the distribution network will result in various issues associated with their intermittent nature. Energy storage is a vital component for overcoming issues associated with the intermittent nature of such RES. Though stationary battery systems are used as energy storage for such applications, smart energy storage (SES) systems are also becoming popular owing to various advantages and advent of smart grid systems. SES can be achieved by aggregating electric vehicles (EVs) or by using demand response management for loads with large time constants. Aggregated residential refrigerators are potential candidates for creating SES which has virtual storage capacity, unlike EVs. In this study, residential refrigerators are modelled analogously to energy capacity and self-discharge of electro-chemical batteries using the artificial neural network based kWh modelling. The model is further extended to estimate the virtual energy storage (VES) capacity with aggregated residential refrigerators; particularly in high-rise residential buildings. Simulation results are presented for scenarios covering the complete range of thermal capacity of typical refrigerators applicable in Singapore's climatic condition. Furthermore, a brief description of the possible applications for the estimated VES, pertaining to smart grid architecture and cyber-attack is also presented

The responses of macroalgae to ocean acidification could be altered by availability of macronutrients, such as ammonium (NH4+). This study determined how the opportunistic macroalga, Ulva australis responded to simultaneous changes in decreasing pH and NH4+ enrichment. This was investigated in a week-long growth experiment across a range of predicted future pHs with ambient and enriched NH4+ treatments followed by measurements of relative growth rates (RGR), NH4+ uptake rates and pools, total chlorophyll, and tissue carbon and nitrogen content. Rapid light curves (RLCs) were used to measure the maximum relative electron transport rate (rETRmax) and maximum quantum yield of photosystem II (PSII) photochemistry (Fv/Fm). Photosynthetic capacity was derived from the RLCs and included the efficiency of light harvesting (α), slope of photoinhibition (β), and the light saturation point (Ek). The results showed that NH4+ enrichment did not modify the effects of pH on RGRs, NH4+ uptake rates and pools, total chlorophyll, rETRmax, α, β, Fv/Fm, tissue C and N, and the C:N ratio. However, Ek was differentially affected by pH under different NH4+ treatments. Ek increased with decreasing pH in the ambient NH4+ treatment, but not in the enriched NH4+ treatment. NH4+ enrichment increased RGRs, NH4+ pools, total chlorophyll, rETRmax, α, β, Fv/Fm, and tissue N, and decreased NH4+ uptake rates and the C:N ratio. Decreased pH increased total chlorophyll content, rETRmax, Fv/Fm, and tissue N content, and decreased the C:N ratio. Therefore, the results indicate that U. australis growth is increased with NH4+ enrichment and not with decreasing pH. While decreasing pH influenced the carbon and nitrogen metabolisms of U. australis, it did not result in changes in growth.

Energy security and climate change issues have increased the call for improved energy efficiency from all sectors of the economy, especially the transportation sector. While vehicle manufacturers can in principle make their current vehicle offerings more fuel efficient, historically they have not done so for reasons of poor auto market sensitivity to fuel economy. However, recent economic events have changed the automobile marketplace. Now, despite current gasoline prices at around $2/gal, there is nonetheless a greater demand for more fuel efficient vehicles, the primary reason for which is anticipation of a return to higher ($3/gal to $4/gal) fuel prices when the recession is over. Unfortunately, simply making the existing fleet of conventional vehicle offerings more fuel efficient will not adequately address energy security and climate change issues. New advanced technology vehicles also need to be considered such as plug in hybrid electric vehicles (PHEV), which hold the promise of considerably improving fleet energy efficiency and reducing fleet carbon footprint. However, because these vehicles cost a lot more than their conventional counterparts, especially in the near term, their market viability is in question, especially if no government policy initiatives are instituted to enable successful market penetration. To address this question, UMTRI has developed an agent based simulation to characterize the penetration of new vehicle penetration into the marketplace under a variety of consumer, economic and policy conditions. Our results show that by 2015, sales could reach 2 – 3 percent with fleet penetration of around 1%. By 2020, sales could reach around 4 – 5 percent with fleet penetration a little more than 2%. And in 30 years, they could be around twenty percent of sales with a fleet penetration of about 16%. Without subsidies, the current policy case would result in a fleet penetration level of less than 1% in ten years. Subsidies are critical; sales tax exemptions can help if applied to scenarios ...

As part of continuous efforts to identify effective and durable anodes for use in cathodic protection (CP) of reinforced concrete bridge members, a water-based, electrically conductive paint was evaluated for use as the secondary anode in CP systems for inland concrete piers. The paint was used in two CP systems—one designed and built approximately 6 years ago and the other 8 years ago—to protect the concrete piers of two pairs of twin bridges in Virginia. When adjusted properly, the two systems provided more than sufficient protection to the reinforcing steel. Natural paint deterioration occurred in both systems. In the 8-year-old system, this deterioration ranged from 0 to 0.37 percent. In the 6-year-old system, it ranged from 0 to 0.14 percent. Most of the deterioration occurred at the ends of the pier caps, where the concrete is not sheltered from rain by a deck overhang. The overall performance of the conductive paint in these CP systems was better than expected. Its effectiveness could last for at least 15 years, even longer if minor paint deterioration is touched up as early as possible. This type of conductive paint should, therefore, be considered a suitable secondary anode for use in CP of inland concrete piers.

Abstract Models of social-ecological systems (SES) are acknowledged as an important tool to understand human-nature relations. However, many SES models fail to integrate adequate information from both the human and ecological subsystems. With an example model of a future Offshore Wind Farm development and its effects on both the ecosystem and local human population, we illustrate a method facilitating a “balanced” SES model, in terms of including information from both subsystems. We use qualitative mathematical modeling, which allows to quickly analyze the structure and dynamics of a system without including quantitative data, and therefore to compare alternative system structures based on different understandings of how the system works. By including similar number of system variables in the two subsystems, we balanced the complexity between them. Our analyses show that this complexity is important in order to predict indirect and sometimes counterintuitive effects. We also highlight some conceptually important questions concerning social compensations during developmental projects in general, and wind farms in particular. Our results suggest that the more project holders get involved in various manner in the local socio-ecological system, the more society will benefit as a whole. Increased involvement through e.g. new projects or job-opportunities around the windfarm has the capacity to offset the negative effects of the windfarm on the local community. These benefits are enhanced when there is an overall acceptance and appropriation of the project. We suggest this method as a tool to support the decision-making process and to facilitate discussions between stakeholders, especially among local communities.

Solar distillation is a practical alternative for freshwater production in arid zones where seawater is abundant. The attractiveness of this approach resides in the simplicity of the solar still, equipment used to produce saline-free water for drinking, intensive agriculture, domestic use and other purposes. A solar still is an apparatus exposed to solar radiation that consists essentially of a basin with a solar collector where saline water is deposited and covered with a transparent inclined glass plate. The system operates as a greenhouse where the heated seawater evaporates and condensates on the inner surface of the cover. The distillate yield is collected in an external container. A research group in Mexico has been working for years doing research on the process of freshwater production with solar stills. Various research aspects have been addressed, among which are mathematical modeling of the physical phenomenon, practical research by building solar stills with different geometries and sizes, and the proposal of a process for mass-production manufacturing of solar stills with technology innovations. This paper is an overview of some of the most relevant results obtained by these research efforts.

Infrastructure improvements contributed 0.6 percentage points to the annual per capita growth of Zambia's gross domestic product (GDP) over the past decade, mostly because of the exponential growth of information and communication technology (ICT) services. Poor performance of the power sector reduced the per capita growth rate by 0.1 percentage point. Simulations suggest that if Zambia's infrastructure platform could be improved to the level of the African leader, Mauritius, per capita growth rates could increase by two percentage points per year. Zambia's high generation capacity and relatively high power consumption are accompanied by fewer power outages than its neighbors. But Zambia's power sector is primarily oriented toward the mining industry, while household electrification, at 20 percent, is about half that in other resource-rich countries. Zambia's power tariffs are among the lowest in Africa and are less than half the level needed to accelerate electrification and keep pace with mining sector demands. Meeting future power demands and raising electrification rates will be difficult without increasing power tariffs. Zambia's infrastructure situation is more hopeful than that of many other African countries. Infrastructure spending needs, though large, are not beyond the realm of possibility, and Zambia's resource wealth and relatively well-off population provide a more solid financing basis than is available to many other countries. Zambia's infrastructure funding gap, though substantial, can be dramatically reduced through measures to stem inefficiencies and lower costs.

One of the most encouraging sorts of renewable energy is ocean wave energy. In spite of a large number of investigations in this field during the last decade, wave energy technologies are recognised as neither mature nor broadly commercialised compared to other renewable energy technologies. In this paper, we develop and optimise Power Take-off (PTO) configurations of a well-known wave energy converter (WEC) called a point absorber. This WEC is a fully submerged buoy with three tethers, which was proposed and developed by Carnegie Clean Energy Company in Australia. Optimising the WEC’s PTO parameters is a challenging engineering problem due to the high dimensionality and complexity of the search space. This research compares the performance of five state-of-the-art metaheuristics (including Covariance Matrix Adaptation Evolution Strategy, Gray Wolf optimiser, Harris Hawks optimisation, and Grasshopper Optimisation Algorithm) based on the real wave scenario in Sydney sea state. The experimental achievements show that the Multiverse optimisation (MVO) algorithm performs better than the other metaheuristics applied in this work.